Intermittingly-acting tension



(No Model.)

G. A. FLBHARTY.

,I-NTERMITTINGLY ACTING TENSION.

No. 345,581. Patented July 13, 1886.

WITNESSES g l/Vgi/VTO n. PETERS Photo-Limognphcr. Walhlnglon. 0.1:.

UNITED STATES PATENT OFFI E.

GEORGE A. FLEHARTY, OF CLEVELAND, OHIO, ASSIGNOR TO JOSEPH FEUSIER, I

OF SAME PLACE, FREDERICK K. HURXTHAL, OF CANTON, OHIO, AND SAMUEL L.'BOGGS, OF PITTSBUEG, PENNSYLVANIA.

, lNTERMtTTlNGLY-ACTING TENSION.

SPECIFICATION forming part of Letters Patent No. 345,581, dated July13,1886.

Application filed October 22, 1885. Serial No. 180,606. (No model.)

To all whom it may concern.-

Be it known that I, GEORGE A. FLEI-IARTY, of Cleveland, in the county ofCuyahoga and State of Ohio, have invented certain new and usefulImprovements in Intermittingly-Acting Tensions for Sewing-Machines; andI do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it pertains to make and use the same.

My invention relates to an improved intermittingly-acting tension forsewing-machines; and it consists in certain features of construc tionand in combination of parts hereinafter described, and pointed out inthe claims.

In the accompanying drawings, Figure 1 is a side elevation of achain-stitch sewing-machine with my improved tension mechanism attached.Fig. 2 is an enlarged elevation, in section, of the tension mechanism.Figs. 3 and 4 are horizontal sections, respectively, on the lineocx and1 Fig. 2; and Fig. 5 is a detached view showing the opening a and thespindle having a mark thereon.

A represents the arm ofthesewing-machine, and B the rock-shaft thatoperates the needlebar B. The arm A is provided with anupwardly-projecting boss, A, the latter having a vertical central bore,a, and a lateral opeuing, a. I

Cis an annular casing that rests on the boss A, and in which is seatedthe spiral spring 0. The casing has a central opening through the bottomthereof, through which passes the hollow spindle D. The spindle has athumb piece, D, for revolving the same, has lateral slots (1 leadinginto the central chamber, and has an annular groove, d, as shown moreclearly in Fig. 2. The spindle extends well down in the boss A, asshown, and at the lower end receives the rod E, the latter fitting thebore of the spindle nicely. The rod E is pivoted to the eccentric-strapE, that engages the eccen tric b on the rock-shaft B. The upper end ofthe rod E has a threaded hole that receives the screw end of the bolt F.The upper end or head of this bolt has a lateral hole, in which isplaced the pin f, that extends through the slots 01 of the spindle andinto the groove 9 of 'tical displacement.

the follower G. The latter is an annular block, shaped substantially asshown in Fig. 2. The follower rests upon the spring 0, and above abutsagainst the lower tension-plate, H. The groove 9 is merely a deepchannel across the center of the follower to accommodate the ver- 5 5tical movement of the pin f. The upper tension-plate, H, is held down bythe collar h, the latter engaging the thumb-piece D. The arrangement issuch that in assembling the parts the spindle D is pressed down,carrying with it of course the tension-plates and follower G, so as tocompress the spring a to such an extent that a thread between the platesH and His held rigidly. In such depressed position of the spindle theannular groove d is engaged by the set-screw I. This set-screw (shownmore clearly in Fig. 4) has a shank, t, that is slightly conicalwhere itengages the groove (1.

The threaded end,that is of considerablelength, enters a threaded holein the boss A, as shown. Vhen this screw is turned in, the conical part1' is pressed into the groove d and locks the spindle D, and preventsthe latter from turning. By backing out the screw I a trifle the spindleis released, so that it may be turned. 7 Meanwhile the part 13, althoughfitting the groove (1 loosely, holds the spindle from ver- If the end ofthe set-screw engaged the groove (2, the latter being necessarilyshallow, if the set-screw were backed out a trifle too much, thevertical adjustment of the spindle would be lost, and the recoil of thespring would probably throw the spindle entirely out of place andscatter the parts. With the arrangement shown the taper of the conicalpart t is so slight that the screw. might be given several revolutionsbefore backing it far enough to be wholly disengaged from the groove (2,so as to lose the vertical adjustment of the spindle. The greatadvantages of this arrangement will more fully hereinafter appear.

By reason of the pin f extending through the head of the bolt F, andalso through the slots d of the spindle, it is evident that the boltwill turn with the spindle, and that by means of the thumb piece D thebolt may be turned to screw it into or out of the rod E, so'as tolengthen or shorten the connection with the eccentric-strap. Thisconnection having been adjusted and the eccentric having been suitablyadjusted on the rockshaft B, the relation of parts is such that when asupply of thread is wanted at the needle the downward throw of theeccentric causes the pin f to depress the follower, thereby reducing thepressure of the disks H and H on the thread to a suitable tension. Areverse in ovement of the shaft 13 and eccentric causes the pinf to belifted from the follower, when the recoil of the spring again pressesthe tensionplates firmly upon the thread, the pinf meantime moving up inthe slots 11 and in the groove 9.

The adjustment aforesaid, that will give a suitable tension for allordinary work, is made at the factory, and a letter or mark is made onthe spindle opposite the hole a, and when such letter, mark, orcharacter is seen through said hole it denotes that the tension deviceis in its normal position. Now, if for any reason a lighter tension isrequired, the set-screw I is loosened, (that is, backed out a trifle,)and the spindle D is turned in the direction that screws in the bolt F,which will of course shorten the eonnectingrod, so that the throw of thecam will further depress the follower, and the disks will only grasp thecotton for a short space of time. Vhen the screw-bolt is unscrewed moreor less, then the grasp of the tension-disks extends for alonger periodthan that of the eccentric passing the upper deadcenter-that is,itoccupies the ti me immediately preceding the arrival of the eccentric atthe upper dead-center, the time of passing it, and a certain length oftime thereafter, thus allowing a longer period of tension on the thread.Such adjustments of the tension are usually only required temporarily,and to return the parts to their normal adjustment the operator has onlyto turn back the spindle until the mark appears in the opening a.

have then a tension device automatic in its 5 functions, that can easilybe changed to give the desired tension, and can as easily be returned toits normal position and without anyliability of losing the verticaladjustment of the spindle or displacement of the parts.

\Vhat I claim is- 1. In an intcrmittingly-acting tension forsewing-machines, the combination, with tension-plates held rigidly fromabove a follower and spring for supporting the plates from below, of aneccentric mounted on the rockshaft, an eccentricstrap, and adjustableconnceting-rod, said rod having a lateral pin for engaging the followerwhen the pin is depressed, the parts being arranged substantially asindicated,whcreby the spring is more or less depressed to give therequired tension, according to the length to which the connecting-rod isadjusted.

2. The combination,with the tension-plates and the spindle D, having anannular groove, (1, of the set-screw l, the latter having a conicalshank for engaging said groove, the parts being arranged substantiallyas set forth.

3. The combination, with the tension-plates, the spindle D, groove (1,and set-screw I, arranged substantially as indicated, of the orifice aand mark on the spindle to indicate, as seen through the opening, thenormal position of thelatter, substantially as described.

4. The combination, with the tension-plates, the spindle D, and rod E,of the casing G, a spiral spring seated therein, the follower resting onsaid spring,and the bolt F, adj ustably sc cured to the rod E andengaging the follower, substantially as set forth.

In testimony whereof I sign this specification, in the presence of twowitnesses, this (3th day of October, 1885.

GEORGE A. FLEIIARTY.

Witnesses:

CHAS. H. Donna, ALBERT E. LYNCH.

